Two-photon imaging can provide dynamic information about the behavior of pathogens and immune cells in tissues during infection. Such information can provide unique insight into the course of events during infection and the impact of therapeutic treatments. However, this technique is outside the reach of many investigators due to the cost of purchasing and maintaining equipment, and the challenges in preparing samples and analyzing data. In this proposal we plan to make this powerful tool available to the investigators of the PO1 by: (1) working with individual labs on pilot studies to determine the optimal experimental set-ups to meet individual imaging goal, (2) expanding existing imaging equipment to provide more access, and (3) assisting individual labs to make use of quantitation software and perform mathematical analysis of visual data.